Halifax Regional Police are being criticized for not tracking drink-tampering incidents in the city, amid multiple reports of spiked drinks at downtown bars and an emergency room doctor who says it happens regularly.

Two women came forward this spring after they were allegedly slipped an unidentified substance at a packed Halifax cabaret, prompting several women to speak out about similar experiences: Blacking out after only a few drinks, sleeping long stretches and recalling nothing from the night before.

Some women told The Canadian Press they were carried home by friends. Others awoke to unfamiliar surroundings with no memory of how they got there or what occurred.

As the number of anecdotal cases involving so-called date rape drugs rose, a police spokeswoman said in April that drink tampering "is not something that we hear of often."

In fact, a Canadian Press request under the Freedom of Information Act has revealed that Halifax police don't track drink tampering.

Police were unable to provide statistics on drink spiking "due to not having the field" to compile reported incidents, Insp. Donald Moser said in a letter.

Tallying up reports of drink tampering would require police to "read through individually" thousands of files, which could cost thousands of dollars, he said.

In a recent email, spokeswoman Const. Carol McIsaac said she consulted the force's watch commanders and members of the Sexual Assault Investigation Team, Liquor Enforcement Unit and Crime Analyst Unit before saying drink tampering was uncommon.

But she confirmed: "We do not have detailed data on the specific issue."

The police response is being criticized by data management experts, who say any suspected crime reported to police should be tracked.

It also appears the police assertion that drink tampering is uncommon is out of step with the experience of some front-line hospital staff in Halifax.

"It worries me very much," said Dr. Sam Campbell, the chief of emergency at the QEII Health Sciences Centre Halifax Infirmary. "I have the feeling it's happening a lot, because many women say they hesitate to come to the hospital at all and even fewer would want to report it to police."

Paige Fitzpatrick, who along with Brittany Bernard shared her experience of a suspected drink tampering incident in April, called it a shame that police don't keep statistics on drink tampering incidents.

The story of the young women, accompanied by photos of them recovering in hospital, was shared thousands of times on Facebook. They reported the alleged crime to police -- although it now appears their experience won't be included in statistics.

"It does indeed seem problematic for the police to make claims about the relative rarity of a particular crime without having data at hand to support those claims," said Ryan Whalen, an adjunct professor at Dalhousie University's School of Information Management.

"In situations like this, citizens have very little insight into the issue and can only really turn to the police or the rumour mill to get a sense of the relative severity of the problem."

Although he said freedom of information requests can demand substantial resources from public organizations, he said the police response suggests a data management problem.

It could be a simple fix, suggests Louise Spiteri, associate professor of the Dalhousie school.

Depending on the force's data management system, "it could be something as simple as adding a drink tampering field," she said. "The bottom line is if it's being reported, it should be recorded."

The advantage of capturing the data in a unique field is it allows police to track patterns such as when drink tampering occurs, the demographic most impacted, and other variables, Spiteri said.

"Particularly in a place like Halifax where it's such a university town and you have a lot of students coming away from home for the first time ... there's a lot of drinking that goes on," she said.

There's no uniform approach to tracking drink tampering incidents in Canada. Police departments contacted by The Canadian Press offered a variety of responses on whether they tracked drink spiking or could provide statistics.

Fredericton police, for example, track drink tampering under a field called administering a noxious substance, but there were none reported in 2017.

Ottawa police did not have the data on hand but indicated that a formal request for a records search would likely provide information as administering a noxious substance is a Criminal Code offence.

Toronto police were able to provide overall numbers for reports of administering a drug for sex and administering a noxious substance. Last year, they received 478 reports of a drugging, which includes drink tampering but also other uses of a drug such as food tampering or a cloth over a mouth.

Vancouver police quickly provided drink tampering stats, but only when the reports were tied to an alleged sexual assault. In 2017, for example, 17 reports of sexual assault involved a suspected drugging.

Meanwhile, Winnipeg police said they do not keep these type of statistics, while Montreal police were also unable to provide any data.

The QEII hospital doesn't keep statistics on incidents involving possible date rape drugs, sometimes called roofies, which include rohypnol, ketamine and gamma hydroxybutyric acid (GHB).

Campbell said they are extremely difficult to test for because they are rapidly absorbed and metabolized by the body. Also, he said there are several other drugs that can be used, making it challenging to know what to test for.

"Some of them are tasteless and they dissolve easily in liquid, they are extremely efficient and would be very easy to slip into someone's drink," he said. "It's a very, very difficult diagnosis to make."

Campbell said in some cases a woman will arrive unsure of what happened, and in other cases a mother will bring her daughter to the emergency department.

"The most common one I would say happens a couple of times a month is someone says, 'I was at a bar and the next thing I know my friend had to carry me home, I don't remember a single thing about it, I had been drinking but not nearly as much as I usually drink,"' he said.

With so little to go on, Campbell said doctors often "shrug and say, 'Well this is probably what happened."'